Mailbox support



FIG. 1 is a perspective view of the mailbox support;

FIG. 2 is a top plan view;

FIG. 3 is a bottom plan view;

FIG. 4 is a front elevational view;

FIG. 5 is a side elevational view; and,

FIG. 6 is a rear elevational view.

The broken lines are included for the purpose of illustration and form no part of the claimed design. 

The ornamental design for a mailbox support, as shown and described. 